BUY H21A2 https://www.utsource.net/itm/p/848068.html
Slotted Optical Switch; Package: Slotted Switch H21; No of Pins: 4; Container: Rail
H21A2 is a 4-pin DIP (dual in-line package) optocoupler manufactured by Fairchild Semiconductor. It is an optically isolated, high-speed, low-current, and low-cost optocoupler. Description: The H21A2 consists of an infrared LED optically coupled to a high gain phototransistor. It is designed for high-speed, low-current applications. Features: - Low input current: 5mA - High isolation voltage: 5000Vrms - High speed: 1.2μs - Low cost Applications: The H21A2 is commonly used in applications such as motor control, power supplies, and industrial automation. It is also used in medical equipment, telecommunications, and automotive applications. (For reference only)